Ok... To give a little context, the Dark King is the fifth Chaos God, it is the God of human ruin, the first was believed to be Horus but in reality it was the Emperor because he began to take the energies of the warp without limit. While absorbing all that energy, the Emperor's radiance could kill and if something saw it for just a nanosecond it could fry your mind, its light reached Sanguinius and Dorn who were within multiple dimensions, in fact Dorn's dimension is one in which which is an endless desert and had been there for centuries. The Dark King makes the other gods look like ghosts and the universe cannot contain him. With that power the Emperor can affect the subatomic particles of the entire universe. Among other things, he is emphasized as the most powerful being, such as Horus collapsing time and reality in the solar system or the fact that he created a world without stars. He should also have all the psychic powers, time stop, mindfuck, transmutation...
